SOLUTION: The area of a circle is 16pi Square feet. Find the radius of the circle.

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Question 189850This question is from textbook Algebra 1 An Incremental Development
: The area of a circle is 16pi Square feet. Find the radius of the circle. This question is from textbook Algebra 1 An Incremental Development

Found 3 solutions by jim_thompson5910, nerdybill, solver91311:
Answer by jim_thompson5910(35256) About Me  (Show Source):
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A=pi%2Ar%5E2 Start with the area of a circle formula


16%2Api=pi%2Ar%5E2 Plug in the given area A=16pi


%2816%2Across%28pi%29%29%2Fcross%28pi%29=%28cross%28pi%29%2Ar%5E2%29%2Fcross%28pi%29 Divide both sides by pi (which cancels out)


16=r%5E2 Simplify


4=r Take the square root of both sides (we're only considering the positive square root)


r=4 Rearrange the terms.


So the radius is 4 feet

Answer by nerdybill(7384) About Me  (Show Source):
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The area of a circle is 16pi Square feet. Find the radius of the circle.
.
Since the formula for the area of a circle is:
(pi)r^2
.
we have:
(pi)r^2 = 16(pi)
dividing both sides by pi:
r^2 = 16
taking the square root of both sides:
r = 4 feet

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


The area of a circle is given by:



Solving for r

Divide both sides by π



Take the positive square root:



Now just substitute your given value for the area and do the arithmetic.

John